PRIVATE eye Bo Dietl badgered the producers of “The Sopranos” so incessantly for a part that they not only stopped taking his calls, but also wrote his friend, Frank Pellegrino, out of the HBO show, a source says. Pellegrino – owner of Rao’s, the clubby East Harlem restaurant where Dietl is a regular – played a high-ranking FBI agent on the series. But he disappeared from the show a couple of years ago, and wasn’t on stage at Radio City with the rest of the cast for the launch of the final season. Dietl, the former police detective lionized in the book/movie “One Tough Cop,” admitted to us, “Anybody would have liked to be in it. I told [‘Sopranos’ creator David] Chase I’d play anything.” But Dietl denied he was responsible for Pellegrino being dropped: “Frankie was sick and he was opening Rao’s in Vegas.” We tried reaching Pellegrino at Rao’s, but the recording says the eatery is fully booked for 2007 and no one would be responding to messages.